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CUMULATIVE IMPACT ASSESSMENTS

PRINCIPLES AND METHODS

Medellin, Nov 2017Brian Glover

Associate professor NTNUBærekraftig Investering AS

[email protected]

• Water sector cumulative impacts1

• Principles and approaches2

• Examples from Norway and othercountries3

Cumulative impact principles and methods

1. WATER SECTOR CUMULATIVE IMPACTS

Why do we need cumulative EIAs?

• Human populations are increasing and the density ofhuman infrastructure is increasing in all countries.

• Individual EIAs are now considered inadequate in most circumstances since they seldom consider thewider long-term impact on a vulnerable ecosystem, habitat or species

• The «bit by bit» erosion of undisturbed land, rivers, lakes and habitats is a threat to biodiversity and willcontinue despite each individual EIA proclaiming thattheir project has «an insignificant impact»

UK survey of EIAs (Cooper and Sheate,2002)

• Only 48% made any mention of cumulative effects

• 8% offered their own definition of cumulativeeffects and they all differ

• Almost all commented on lack of guidance onmethods for CumEIA, both in UK and abroad

• Only 6% provided any systematic analysis of CumEIA

• All CumEIA analysis was qualitative based on expertjudgement and carefully worded conclusions

Cumulative effects poorly defined?

• Cumulative effects have been discussed for several decades, but no generally agreeddefinition has been accepted.

• 1969 definition in UK Environmental policy:– «the impact on the environment which results

from the incremental impact of the action whenadded to past, present and reasonablyforeseeable future actions»

Common elements in most definitions

• The ecosystem approach turns the focus away from an individualproject impact to a focus on a specified valuable ecosystem, habitat or vulnerable species

• holistic understanding of all impacts on the ecosystem beinganalysed

• Not limited in time or space, other than what the particularecosystem limits naturally are.

• All past, present and reasonably foreseeable future impacts to be considered

• Synergies between different impacts and species must be assessed in a biological context, not simply summed linearly

EU Guidance from 1999

Definition from EU, 1999 guidance

Not necessarily arithmetically addableInteractions = synergies.(1+1 might be 3 or might be 1.1!)

from EU, 1999 guidance

Increasing complexity and importance

Starting point

Principles of CIAIFCs Good Practice Handbook for CIA

2

Distinctions betweenESIA, SEA, CIA (EGIA en espanol)

VECs – Valued Environmental and social Components

• Componentes ambientales y socialesvalorados en espanol

Different perspective from ESIA

Project-centred perspective of the ESIA

VEC- centred perspective of the CIA

Several projects and pressures on same VEC

Six step approach to CIA• IFCs Good Practice Handbook can be

downloaded in English and Spanish from• http://www.ifc.org/wps/wcm/connect/topics_ext_content/ifc_external_corporate_site/sus

tainability-at-ifc/publications/publications_handbook_cumulativeimpactassessment

IFCs approach to encouraging CIA

River basin approach to Cum EIA

• Most impacts on aquatic systems do not addlinearly to a sum of impacts. Trend analysis?

Time boundary or horizon for CumEIA

• Back in time: generally the last 30-50 years

• Forward in time depends……………

The important aspect is not to include unrealistic or non financeable projects/ impacts

(generally on future plans for infrastructure)

Time boundary definitions (hydro)

• Hydropower has long lead times (10-15 years)• Recommended planning horizon is normally 20 years• Objective of CumEIA time horizon definition is to describe the

probable future scenario in the normal planning horizon of 10-20 years. Impacts from projects may change in form, but the projectsshould not be dropped. Reasonable chance of being constructed

• General hydro resource mapping and reconnaissance studies are toovague to include in CumEIA analysis

• Minimum requirement for project inclusion in CumEIA is that there is an internationally approved pre-feasibility study report available from which to guess the project’s impact

• All projects with approved feasibility reports (incl. EIA) can and shouldbe included in CumEIA unless there are good grounds to assume theproject will not be built in next 20 years.

Who should carry out CumEIA?

• Historically has fallen on each project developer to describe CumEIA.

• This has not worked well. Developer (and theirconsultant) tends to over-simplify the CumEIA and/or downplay the cumulative effects or synergies

• Each developer may not have full information onother (competing?) project plans.

• The government agencies or financing institutionsshould take over role as client for CumEIA studies, requiring open access to all impact information from all projects

1. Scoping. Spatial analysis (GIS)

• What relevant information is available from maps and GIS?

• Make a spatial representation of all relevant information, and superimpose all impacts

• Examples: nature types in Norway, forest cover, important habitats, nesting sites, territorial preditor densities,

• Modern GIS databases make this type of analysisvery important and give a vital overview ofpotential cumulative effects

Overlay of relevant GIS datasets are onlya start, limitations later in the analysis

National parks and nature reserves

3. EXAMPLES FROM MEKONG

AND NORWAY

Cum EIA – relevance for hydropower

• Some situations in hydropower countriesrequire cumulative analysis of many impacts/ projects on a vulnerable ecosystem / species

• Typically many hydros or dams on the same river (example Mekong)

• Many small hydros with small individualimpacts may have cumulative destructiveimpact on for example fish stocks

Radiotagged fish studies, Norway70 km of river available, 3 hydros planned

• Grayling Trout

One of the 3 hydro plans

Planned hydropower

development in Mekong

basin

•Many plans for Lao PDR

•Large storage schemes in

China

•Some development plans in

Cambodia and Vietnam

VEC: Riverbank and flood plain

agricultural practice

• This is a

Dry season irrigation of

flood plains

Hydrological structure

Nam Kathang

Area for Water

Balance

Modelling

Area for

Hydraulic

Modelling

NT2 site

MikeBasin

Mike 11

NT2 impact only: Dry season flows increase 5-10%

CIA results for 2025: 150% increase dry season

2025: 130% increase along most of Mekong

Mekong River regulatedmuch more

Yellow is % increase in

dry season flow

Blue is % decrease in

Wert season flow

But…big changes in Tonle Sap lake

Flooding and Floodplain Fisheries

Over 1 m reduced amplitude of lake levels as a

result of all reservoirs. 900 km2 less flooded area.

Big impact on fisheries

Planned tributary projects

General Findings, Conclusions and Recommendations - Cascade Scale

The extensive and detailed assessment carried out in this study further

concludes that:

o The mitigation options tested reduce the downstream impacts compared to

“no mitigation” scenario to varying degrees;

o The investment in the cost of construction and operation of the mitigation

solutions is well justified by the value and benefits from reduced

environmental impacts in the cascade reach and further downstream;

o There remains a number of basin scale impacts from the Lao mainstream

cascade that cannot be fully mitigated (for example transport of coarser

sediments).

CUMULATIVE IMPACT

ASSESSMENTS:PRINCIPLES AND METHODS

Thank you!Bærekraftig Investering [email protected]